Qhov sib txawv tseem ceeb ntawm de novo thiab txoj kev cawm seej yog qhov novo synthesis ntawm purine nucleotides hais txog cov txheej txheem uas siv cov khoom me me xws li phosphoribose, amino acids, CO 2thiab lwm yam. Raws li raw cov ntaub ntawv los tsim purine nucleotides, thaum txoj kev khaws cia ntawm purine synthesis yog hais txog cov txheej txheem uas siv purine bases thiab purine nucleosides thiaj li yuav tsim purine nucleotides.
Nucleotides yog lub tsev thaiv ntawm nucleic acids. Ntxiv mus, qee cov nucleotides, tshwj xeeb tshaj yog ATP, muaj lub luag haujlwm tseem ceeb hauv kev hloov hluav taws xob. Ib txhia ua hauj lwm raws li ob tug tub txib ib yam nkaus. Lub nucleotide muaj peb yam: qab zib, nitrogen puag thiab phosphate pawg. Synthesis ntawm nucleotides tshwm sim ntawm txoj kev sib txawv. De novo txoj kev thiab txoj kev cawm seej yog ob txoj hauv kev tseem ceeb ntawm kev sib txuas ntawm purine nucleotides. De novo txoj kev ua raws li txoj hauv kev tseem ceeb thaum txoj kev khaws cia yog qhov tseem ceeb rau purine nucleotide synthesis hauv lub hlwb thiab cov pob txha pob txha. Yog li ntawd, txoj kev de novo yog txoj kev loj thaum txoj kev cawm seej yog txoj kev me.
Txoj Kev De Novo yog dab tsi?
De novo txoj kev yog txoj hauv kev metabolic uas pib nrog cov molecules me me thiab sib txuas cov molecules tshiab. Yog li, de novo synthesis ntawm purine nucleotides hais txog cov txheej txheem uas siv cov molecules me los tsim purine nucleotides. Nws siv raw cov ntaub ntawv xws li phosphoribose, amino acids (glutamine, glycine, thiab aspartate), CO 2, thiab lwm yam, los ua ke purine nucleotides. Ntxiv mus, txoj kev de novo yog txoj hauv kev tseem ceeb uas tsim cov purine nucleotides.
Daim duab 01: De Novo Synthesis ntawm Purine Nucleotides
Nyob rau hauv de novo txoj kev, ribose -5-phosphate ua haujlwm raws li cov khoom pib. Tom qab ntawd, nws reacts nrog ATP thiab hloov mus rau phosphoribosyl pyrophosphate (PRPP). Tom ntej no, glutamine pub nws cov pab pawg amide rau PRPP thiab hloov mus rau 5-phosphoribosylamine. Tom qab ntawd, 5-phosphoribosylamine reacts nrog glycine thiab dhau los ua glycinamide ribosyl 5-phosphate, thiab tom qab ntawd, nws hloov mus rau hauv formylglycinamide ribosyl 5-phosphate. Glutamine pub nws cov pab pawg amide thiab hloov cov formylglycinamide ribosyl 5-phosphate rau hauv formylglycinamideine ribosyl 5-phosphate. Tom qab ntawd lub nplhaib imidazole ntawm purine ua tiav nws daim ntawv nplhaib. Thaum kawg, nrog kev koom ua ke ntawm CO 2 thiab tau txais ntau qhov kev tawm tsam ntxiv, nws dhau los ua inosine monophosphate (IMP). IMP yog qhov tam sim no precursor molecule ntawm adenosine monophosphate (AMP) thiab guanosine monophosphate (GMP), uas yog purine nucleotides.
Txoj kev cawm seej yog dab tsi?
Txoj kev cawm ntawm purine nucleotide synthesis yog hais txog cov txheej txheem ntawm kev sib txuas nucleotides los ntawm purine hauv paus thiab purine nucleosides. Purine bases thiab purine nucleotides yog tas li tsim nyob rau hauv lub hlwb raws li cov metabolism hauv nucleotides xws li polynucleotide degradation. Ntxiv mus, cov hauv paus thiab nucleosides kuj nkag mus rau peb lub cev los ntawm cov zaub mov peb noj.
Daim duab 02: De Novo thiab Txoj Kev Txum Tim
Txoj kev cawm ntawm purine nucleotide synthesis yog ib txoj hauv kev me. Nws tshwm sim los ntawm phosphoribosyltransferase cov tshuaj tiv thaiv. Ob lub enzymes tshwj xeeb, adenine phosphoribosyl transferase (APRT) thiab hypoxanthine-guanine phosphoribosyl transferase (HGPRT), catalyze cov tshuaj tiv thaiv phosphoribosyltransferase. Lawv catalyze hloov pauv ntawm ribose-5'-phosphate moiety los ntawm phosphoribosyl pyrophosphate (PRPP) mus rau purine bases kom tau txais purine nucleotides. Txoj kev khaws cia yog qhov tseem ceeb hauv qee cov ntaub so ntswg uas de novo synthesis tsis tau.
Dab tsi zoo sib xws ntawm De Novo thiab Txoj Kev Salvage?
- De novo thiab kev cawmdim yog ob txoj hauv kev ntawm nucleotide synthesis.
- Ntxiv mus, ob qho tib si sib sau ua ke ribonucleotides uas tuaj yeem siv los ua ke deoxyribonucleotides rau DNA.
- Tsis tas li ntawd, kev tawm tswv yim inhibition tswj ob txoj hauv kev.
Qhov txawv ntawm De Novo thiab Txoj Kev Salvage yog dab tsi?
Nucleotide synthesis tshwm sim ntawm ob txoj hauv kev: de novo txoj kev thiab txoj kev khaws cia. De novo txoj kev siv cov molecules me me los tsim cov nucleotides, thaum txoj kev khaws cia siv cov hauv paus ua ntej thiab nucleosides los tsim cov nucleotides. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm de novo thiab txoj kev cawm seej.
Tsis tas li ntawd, lwm qhov sib txawv tseem ceeb ntawm de novo thiab txoj kev cawm seej yog txoj kev de novo tshwm sim hauv txhua hom cell thaum txoj kev khaws cia tshwm sim hauv qee cov ntaub so ntswg uas de novo txoj kev tsis tuaj yeem ua tau. Ntxiv mus, txoj kev de novo yog txoj hauv kev loj thaum txoj kev khaws cia yog txoj kev me me ntawm nucleotide synthesis.
Cov ntaub ntawv hauv qab no-daim duab qhia ntau qhov kev sib piv ntsig txog qhov sib txawv ntawm de novo thiab txoj kev cawm seej.
Summary – De Novo vs Salvage Pathway
De novo txoj kev yog txoj hauv kev tshiab ntawm kev sib txuas ua ke ntawm cov khoom me me. Txoj kev Salvage yog ib txoj hauv kev uas siv cov khoom sib txuas ua ntej los ua ke kom sib xyaw ua ke. Hauv kev sib xyaw nucleotide, ob qho tib si de novo thiab txoj kev khaws cia tau pom. Yog li, de novo txoj kev ntawm purine nucleotide synthesis yog hais txog cov txheej txheem uas siv cov molecules me me xws li ribose qab zib, amino acids, CO 2, ib chav tsev carbon, thiab lwm yam. los tsim cov purine nucleotides tshiab. Ntawm qhov tod tes, txoj kev khaws cia ntawm purine nucleotide synthesis yog hais txog cov txheej txheem uas siv cov hauv paus ua ntej thiab nucleosides los tsim cov purine nucleotides. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm de novo thiab txoj kev khaws cia. Tsis tas li ntawd, txhua hom cell muaj peev xwm ua tiav txoj hauv kev de novo thaum tsuas yog qee cov ntaub so ntswg tuaj yeem nqa txoj hauv kev khaws cia.
